Advances in semiconductor manufacturing technology have resulted in, among other things, reducing the cost of sophisticated electronics to the extent that integrated circuits have become ubiquitous in the modern environment.
As is well-known, integrated circuits are typically manufactured in batches, and these batches usually contain a plurality of semiconductor wafers within and upon which integrated circuits are formed through a variety of semiconductor manufacturing steps, including, for example, depositing, masking, patterning, implanting, planarizing, etching, and so on.
Completed wafers are tested to determine which die, or integrated circuits, on the wafer, are capable of operating according to predetermined specifications. In this way, integrated circuits that cannot perform as desired are not packaged, or otherwise incorporated into finished products.
It is common to manufacture integrated circuits on roughly circular semiconductor substrates, or wafers. Further, it is common to form such integrated circuits so that conductive regions disposed on, or close to, the uppermost layers of the integrated circuits are available to act as terminals for connection to various electrical elements disposed in, or on, the lower layers of those integrated circuits. In testing, these conductive terminals, sometimes referred to as bond pads or probe pads, are commonly contacted with a probe card.
Today's tester technology often lacks the ability to test an entire wafer at one time. Therefore, most wafers are tested one or several die at a time. This less than full-wafer testing approach requires that the probes be stepped from one location on the wafer to another during the testing process in order to test the entire wafer. Current wafer probing technology requires very accurate placement of the probes onto the wafer to make electrical contact. Stepping the probes on the wafer requires that a high accuracy probing system be dedicated to each wafer under test. The cost and complexity of these probing systems has a large impact on the overall cost of producing the devices themselves.
What is needed are lower-cost, less-complex apparatus and methods to increase test efficiency.